Natural Coating Protects Wood Floors from Sun


Scientists in Germany are working to create a new coating to protect wood from ultraviolet radiation while maintaining the look of natural wooden surfaces.

The team comprises of researchers from the Fraunhofer Institute for Process Engineering and Packaging IVV and Naturhaus Naturfarben GmbH, aiming for a formula that provides harmless, transparent and 100% organic UV protection for wood.

About the Project

Popular open architecture with glass facades and big windows let natural light flood into home interiors; however, without a coating, UV light ranging from 330 to 380 nanometers in wavelength can interact with wood surfaces, causing discoloration and damage through a process known as photooxidation.

According to Fraunhofer, currently available transparent protective coatings contain harmful chemical additives such as benzophenones, benzotriazoles or phenyltriazine derivatives. Additionally, so far, all bio-based alternatives to protect wood against aging due to sunlight have been colored and opaque.

The team then tasked themselves with finding suitable plant-based components for a natural wood finish that would protect the material against UV radiation while still leaving the grain visible for the ProTann project.

“For natural binding in coating systems, we’ve had great success with using proteins at Fraunhofer IVV for quite some time now,” explained Melanie Platzer, a research scientist in the Process Development for Plant Raw Materials department. “One thing that was new for us was combining proteins with secondary plant-based materials that serve as UV protection for a water-based finish.”

One of the project’s goals was reportedly to work out the cross-links created between the proteins and secondary plant-based materials in the finish and ultimately ensure that the substances formed a permanent bond. 

The researchers first tested their initial formulation idea, which built on a previous Fraunhofer project that used multiple proteins, such as pea and soy protein.

“We had a few crucial questions during this phase. Does the coating produced adhere to wood? Does it absorb? And can it be removed so the UV-blocking effect can be measured in the first place?” Platzer commented.

Then, the project team selected two proteins and added various secondary plant-based substances that offer good protection against UV radiation. According to the study, the pH presented a challenge since wood finishes have to fall within a certain range so they do not harm the material.

Adding the plant extracts themselves was also reportedly a crucial point for the research team, as it was difficult to predict how well the various extracts would dissolve, whether they would interact with the proteins and how the color of the coating created would change over the course of the process.

The scientists tested many combinations over the two-year project term and noted they were highly successful at working with mixtures of different secondary plant-based substances.

“In the end, we had a lot of good candidates for possible combinations of proteins and additives for the UV protective coating, so we were able to zero in on the question of which formulation makes the most sense in thinking about production—including with an eye to local sourcing and availability of the raw materials used,” Platzer said.

“Wherever possible, we include residue from the agriculture and food industry in our development work. That includes things like peels left over from making apple juice, or pomace from wine production.”

The model formula is now reportedly undergoing further development at Naturhaus, with a goal of adapting the composition to be produced on a large scale for the natural wood preservative segment market.

The water-based formula could then be applied in several coats, with a different natural finish on top as a sealant, to provide protection for wood floors and furniture.

Fraunhofer has also reportedly initiated a follow-up project to further develop the many research findings from ProTann. The researchers say that the UV-blocking combinations of proteins and plant substances could also be used to coat packages or in skincare.


Tagged categories: Asia Pacific; Bio-based materials; Coating chemistry; Coating Materials - Commercial; Coatings; EMEA (Europe, Middle East and Africa); Good Technical Practice; Green chemistry; Green coatings; Latin America; North America; Program/Project Management; Research and development; UV resistance; UV resistance; Wood; Wood coatings; Wood stains; Z-Continents

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